1. Field of Invention
This invention relates generally crop sprayer vehicles, and more particularly to a crop sprayer vehicle with a folding boom structure.
2. Description of Related Art
The high crop yields of modern agribusiness typically use applications of fertilizers, pesticides, herbicides, fungicides and other chemicals to protect the crops from diseases and insects and to facilitate the growth and harvest of the crops. Dispersion of these chemicals onto high acreage fields is accomplished by specialized machines mounted on or towed by a vehicle. An example of such a machine is a self-propelled crop sprayer.
A common design for a self-propelled crop sprayer includes a dedicated chassis with a tank, boom arms connected to and extending from the chassis, and spray nozzles connected to the boom arms. The tank contains fluid such as fertilizers, pesticides, and herbicides. Boom arms extend outward from the sides of the dedicated chassis. The boom plumbing includes supply lines and a plurality of nozzles spaced apart along the length of the boom arms. Typically, the nozzles are positioned with a standard spacing distance that corresponds to a spray pattern of the nozzles. In operation, as the crop sprayer traverses a field, fluid is pumped from the tank through the supply lines along the boom arms, and out through the nozzles. This allows the self-propelled sprayer to distribute the fluid along a relatively wide path. The total length (e.g., span) of a conventional boom arm assembly may vary from, for example, 6 meters (18 feet) up to 46 meters (150 feet), but smaller or longer booms are possible. The boom arms typically swing in for transport and out for operation.
FIG. 1 shows a prior art crop sprayer 10 that can be used to deliver chemicals to agricultural crops in a field. Crop sprayer 10 includes a chassis 12 and a cab 14 mounted on the chassis 12. Cab 14 houses an operator and controls for the crop sprayer 10. An engine 16 may be mounted on a forward portion of chassis 12 in front of cab 14 or may be mounted on a rearward portion of the chassis 12 behind the cab 14. The engine 16 may be commercially available from a variety of sources and may comprise, for example, a diesel engine or a gasoline powered internal combustion engine. The engine 16 provides energy to propel crop sprayer 10 and also may provide energy used to spray fluids from the crop sprayer 10.
The crop sprayer 10 further includes a supply vessel or tank 18 to contain a fluid to be sprayed on the field. The fluid may include chemicals, such as but not limited to, herbicides, pesticides, and/or fertilizers. Tank 18 may be mounted on chassis 12, typically either in front of or behind cab 14. Crop sprayer 10 may include more than one tank 18 to store different chemicals to be sprayed on the field. The contained chemicals may be dispersed by crop sprayer 10 one at a time; alternatively, different chemicals may be mixed and dispersed together.
The fluid in tank 18 is conveyed by a fluid supply system and various spray nozzles (not shown), spaced along the boom arms 20. As is known in the art, a pump (not shown) pressurizes and distributes the fluid from tank 18 and through pipes or hoses to the spray nozzles. An operator of the crop sprayer 10 may use controls (not shown) located in the cab 14 to control movement of the boom arm 20 and to turn on and to shut off the fluid flow to the plurality of spray nozzles. Spray controls are described in the following patents, assigned to AGCO Corporation of Duluth, Ga., which are hereby incorporated by reference: U.S. Pat. No. 8,028,927 entitled “Variable Rate Spray Nozzle Control”; U.S. Pat. No. 7,706,926 entitled “Adaptive Feedback Sources for Application Controllers” and U.S. Pat. No. 5,971,294 entitled “Agricultural Application Systems with Improved Spray Control.”
For a boom span of about 120 feet, each of the left and right boom arms 20 is typically about 55 feet long. The width of crop sprayer 10, which is about ten feet in a typical case, is covered by a central spray bar at the rear of crop sprayer 10. For each of the left and right boom arms 20, the boom structure that is proximate the vehicle must be very strong to support the length of the boom arm 20 outward from the attachment structure. Thus, boom structures are typically quite heavy, cumbersome, and expensive.